1. Field
The present general inventive concept relates to an electronic device and a board usable in the electronic device, and more particularly to an electronic device and a board usable in the electronic device having an electrostatic discharge (ESD) and leakage current protection circuit.
2. Description of the Related Art
A conventional electrostatic discharge (ESD) protection device is installed inside an electronic device in order to prevent damage of an internal circuit due to ESD stress current that flows from a charged human body or machine into an inner portion of a semiconductor device.
As technology progresses with regard to system on chip (SOC), an area occupied by an ESD protection circuit is considered when determining an entire size of a semiconductor chip. Further, the importance of the ESD protection circuit has been gradually increasing since the ESD protection circuit acts as an important factor that determines hip performance.
Conventionally, when an exterior portion of a conductive material is mounted on an exterior portion of an electronic device, ESD protection has been applied in various ways.
For example, a part of an exterior portion of an electronic device may be directly connected to a printed circuit board (PCB) ground or a ground of an adapter to allow ESD that is applied to an external case of a conductive material to be discharged to the ground.
Alternatively, an exterior portion of the electronic device and a ground may be spaced apart from each other without being electrically connected to each other to minimize a secondary influence exerted on a main system when ESD is applied to the exterior portion of a conductive material.
However, the above-mentioned ESD protection methods include the following problems.
When a part of an exterior portion of an electronic device is directly connected to a PCB ground or a ground of an adapter, leakage current of the system flows to the exterior portion of the conductive material through a conductor connected between the exterior portion of the conductive material and the ground.
Also, when minimizing a secondary influence on a system when the ESD is applied to the exterior portion of the conductive material by making the exterior portion of the electronic device and the ground spaced apart from each other without electrically connecting the exterior portion of the electronic device and the ground to each other, the ESD that is applied to the exterior portion of the conductive material is not discharged, and thus an electromagnetic field is generated on a surface of the exterior portion of the conductive material to cause signal distortion on the PCB.
Further, if a user physically approaches the exterior portion of the conductive material in a state where electric charge on the exterior portion of the conductive material has not been discharged, the electric charge on the exterior portion of the conductive material may cause secondary discharge to be transferred to the user resulting in a shock.